The role of the Cockayne syndrome proetin

科凯恩综合征蛋白的作用

• 批准号: 7964022
• 负责人: Vilhelm Bohr
• 金额: $ 33.89万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7964022
• 关键词: 8-hydroxyadenine; 8-hydroxyguanosine; ATP Hydrolysis; ATP phosphohydrolase; Age; Aging; Aging-Related Process; Base Excision Repairs; Biological; Biological Models; Brain; Cells; Characteristics; Cockayne Syndrome; Complex; Cyclin-Dependent Kinase 4; DNA; DNA Damage; DNA Excision Repair Protein ERCC-6; DNA Repair Pathway; DNA glycosylase; Disease; Drosophila snf protein; Excision; Lesion; Lyase; Maps; Mitochondrial DNA; Mus; Mutation; Nerve Degeneration; Nuclear; Nucleotide Excision Repair; OGG1 gene; Oxidative Stress; Pathology; Pathway interactions; Patients; Play; Post-Translational Protein Processing; Premature aging syndrome; Process; Protein Family; Proteins; Role; Signal Pathway; Single Strand Break Repair; Syndrome; Tissues; Transcription-Coupled Repair; base; brain tissue; early onset; helicase; human TYRP1 protein; in vivo; interest; novel; oxidative DNA damage; protein function; repaired; response

In CS cells, there are deficiencies in the repair of oxidative DNA damage in the nuclear and mitochondrial DNA, and this may be a major underlying cause of the disease. We found that CSB-deficient cells accumulate oxidized bases, 8-hydroxyguanine and 8-hydroxyadenine, after oxidative stress, consistent with the observation that CSB and oxoguanine DNA glycosylase (OGG1), the major DNA glycosylase for 8-oxoG repair, are in a complex in vivo. We also found that the CSB protein physically interacts with the Nei-like DNA glycosylase, NEIL1, which is also involved in the repair of oxidized bases. This interaction significantly stimulates NEIL1 catalytic activities, both the glycosylase as well as the AP-lyase. The observation that CSB-deficient mice accumulate significantly higher levels of several oxidized DNA bases in brain tissue, including fapyadenine and fapyguanine, supports a role for the CSB protein in the removal of oxidized lesions in vivo. It is notewhorty that Fapy lesions are considered canonical substrates for NEIL1, underscoring the biolgical relevance for this protein interaction. We recently demonstrated that the CSB protein also interacts with PARP1, a protein involved in the early steps of single-strand break repair, and that these two proteins cooperate in the cellular responses to oxidative stress. CSB is a substrate for PARP-1 ribosylation and it is likely that these two proteins function together in the process of base excision. Our results indicate that the CSB protein plays an important role in the repair of oxidative DNA damage and that accumulation of unrepaired lesions, particular in target tissues, like the brain, may be relevant to the CS pathology, which is characterized by severe early onset neurodegeneration. Moreover, we have identified a novel catalytic activity of the CSB protein. Despite having 7 conserved helicase domains (characteristic of the SWI/SNF protein family), the only identified catalytic activity of CSB was ATP hydrolysis. We found that CSB efficiently catalyzes the annealing of two complementary strands of DNA. We are now mapping this novel activity to gain a better understanding of its biological relevance. Repair of 8-oxoG is of special interest since this lesion is believed to be highly mutagenic and accumulates with age. We find that OGG1 interacts with and can be phosphorylated by the cyclin-dependent kinase cdk4. This post-translational modification modulates OGG1 catalytic activity, suggesting a role for signaling pathways in the response to oxidative DNA damage.

在CS细胞中，核和线粒体DNA氧化损伤的修复存在缺陷，这可能是该病的主要潜在原因。我们发现CSB缺陷细胞在氧化应激后积累氧化碱基8-羟基鸟嘌呤和8-羟基腺嘌呤，这与观察到CSB和8-oxoG修复的主要DNA糖基酶OGG1在体内处于一个复合体中是一致的。我们还发现CSB蛋白与Nei样DNA糖基酶NEIL1物理上相互作用，NEIL1也参与氧化碱基的修复。这种相互作用显著地刺激了NEIL1的催化活性，既包括糖基酶，也包括解酶。观察到CSB缺陷小鼠在脑组织中积累了显著较高水平的几种氧化DNA碱基，包括法比腺嘌呤和法比鸟嘌呤，这支持了CSB蛋白在体内清除氧化损伤中的作用。值得注意的是，Fapy损伤被认为是NEIL1的典型底物，强调了这种蛋白质相互作用的生物学相关性。 我们最近证明了CSB蛋白也与PARP1蛋白相互作用，PARP1蛋白参与单链断裂修复的早期步骤，并且这两种蛋白在细胞对氧化应激的反应中相互作用。CSB是PARP-1核糖化的底物，这两种蛋白很可能在碱基切除过程中共同发挥作用。我们的结果表明，CSB蛋白在DNA氧化损伤的修复中起着重要作用，未修复损伤的积累，特别是在靶组织，如脑，可能与以严重的早发性神经变性为特征的CS病理有关。 此外，我们还鉴定了CSB蛋白的一种新的催化活性。尽管CSB有7个保守的解旋酶结构域(SWI/SNF蛋白家族的特征)，但唯一发现的催化活性是ATP水解酶。我们发现CSB有效地催化了两条互补的DNA链的退火。我们现在正在绘制这一新的活动图，以更好地了解它的生物学相关性。 8-oxoG的修复特别有意义，因为这种损伤被认为是高度突变的，并随着年龄的增长而积累。我们发现OGG1与细胞周期蛋白依赖性蛋白依赖性蛋白激酶CDK4相互作用并可被其磷酸化。这种翻译后修饰调节了OGG1的催化活性，表明信号通路在对DNA氧化损伤的反应中发挥了作用。